Methods of cutting fiber reinforced polymer composite workpieces with a pure waterjet

ABSTRACT

Methods of trimming fiber reinforced polymer composite workpieces are provided which use a pure waterjet discharged from a cutting head in liquid phase unladened with solid particles at an operating pressure of at least 60,000 psi and in combination with other cutting parameters to provide a final component profile without delamination, splintering, fraying or unacceptable fiber pullout or fiber fracture.

BACKGROUND

Technical Field

This disclosure is related to high-pressure waterjet cutting systems andrelated methods, and, more particularly, to methods of cutting fiberreinforced polymer composite workpieces with a pure waterjet.

Description of the Related Art

Waterjet or abrasive waterjet cutting systems are used for cutting awide variety of materials, including stone, glass, ceramics and metals.In a typical waterjet cutting system, high-pressure water flows througha cutting head having a nozzle which directs a cutting jet onto aworkpiece. The system may draw or feed abrasive media into thehigh-pressure waterjet to form a high-pressure abrasive waterjet. Thecutting head may then be controllably moved across the workpiece to cutthe workpiece as desired, or the workpiece may be controllably movedbeneath the waterjet or abrasive waterjet. Systems for generatinghigh-pressure waterjets are currently available, such as, for example,the Mach 4™ five-axis waterjet cutting system manufactured by FlowInternational Corporation, the assignee of the present application.Other examples of waterjet cutting systems are shown and described inFlow's U.S. Pat. No. 5,643,058.

Abrasive waterjet cutting systems are advantageously used when cuttingworkpieces made of particularly hard materials, such as, for example,high-strength steel and fiber reinforced polymer composites to meetexacting standards; however, the use of abrasives introducescomplexities and abrasive waterjet cutting systems can suffer from otherdrawbacks, including the need to contain and manage spent abrasives.

Other known options for cutting fiber reinforced polymer compositesinclude machining (e.g., drilling, routing) such materials with carbideand diamond coated carbide cutting tools (e.g., drill bits, routers).Machining forces from such cutting tools, however, can promote workpiecefailures such as delamination, fraying, splintering, fiber pullout,fiber fracture and/or matrix smearing. These types of cutting tools canalso be susceptible to premature wear and must be replaced frequentlywhen cutting fiber reinforced polymer composite workpieces to ensure anacceptable finish, thereby increasing operational costs. Moreover,machining fiber reinforced polymer composite parts with carbide cuttingtools generates dust that can create environmental hazards andnegatively impact machining performance.

BRIEF SUMMARY

Embodiments described herein provide methods of cutting fiber reinforcedpolymer composite workpieces with high-pressure pure waterjets in liquidform unladened with solid particles, which are particularly well adaptedfor trimming thin shelled fiber reinforced polymer composite parts toinclude a final component profile to meet generally accepted industryquality standards, such as quality standards of the automotive industry.

Embodiments include methods of trimming fiber reinforced polymercomposite workpieces with a pure waterjet discharged from a cutting headin liquid phase unladened with solid particles at or above a thresholdoperating pressure of at least 60,000 psi and in combination with othercutting parameters to provide a final component profile withoutdelamination, splintering, fraying or unacceptable fiber pullout orfiber fracture. Advantageously, the use of abrasive media, such asgarnet, may be avoided, which can simplify the cutting process andprovide a cleaner work environment. In addition, fixturing may besimplified when trimming or otherwise cutting with a pure waterjet asthe pure waterjet is less destructive to support structures underlyingthe workpieces.

In one embodiment, a method of trimming a fiber reinforced polymercomposite workpiece may be summarized as including: providing the fiberreinforced polymer composite workpiece in an unfinished state in whichfiber reinforced polymer composite material of the workpiece extendsbeyond a final component profile thereof; generating a pure waterjet viaa cutting head in liquid phase unladened with solid particles at anoperating pressure of at least 60,000 psi; directing the pure waterjetto pass through the fiber reinforced polymer composite workpiece; andmoving one of the cutting head and the fiber reinforced polymercomposite workpiece relative to the other along a predetermined pathwhile maintaining the operating pressure of at least 60,000 psi suchthat the pure waterjet trims the fiber reinforced polymer compositematerial to the final component profile without delamination,splintering, fraying or unacceptable fiber pullout or fiber fracture.

Moving the cutting head and the fiber reinforced polymer compositeworkpiece relative to each other along the predetermined path mayinclude moving at a cutting speed based at least in part on a thicknessof the fiber reinforced polymer composite workpiece and a magnitude ofthe operating pressure. The cutting speed may also be based at least inpart on a type of fiber, a type of matrix material, and/or a type offabrication scheme of the fiber reinforced polymer composite workpiece.The fiber reinforced polymer composite workpiece may include carbonfibers, glass fibers, boron fibers or polyamide fibers, and the fiberreinforced polymer composite workpiece may be built up from layers offibers, tape or cloth impregnated with the matrix material. The cuttingspeed may also be based at least in part on an orifice size of anorifice member used to generate the pure waterjet.

The method of trimming the fiber reinforced polymer composite workpiecemay further include: piercing the fiber reinforced polymer compositeworkpiece at an area within the final component profile at any operatingpressure (including below 60,000 psi) and creating an aperturesurrounded by a localized area of delamination; and moving one of thecutting head and the fiber reinforced polymer composite workpiecerelative to the other along another predetermined path while maintainingoperating pressure of at least 60,000 psi such that the pure waterjetcuts an internal feature within the fiber reinforced polymer compositematerial and removes the localized area of delamination.

The method of trimming the fiber reinforced polymer composite workpiecemay further include, while moving the cutting head and the fiberreinforced polymer composite workpiece relative to each other along atleast a portion of the predetermined path, simultaneously directing agas stream onto an exposed surface of the fiber reinforced polymercomposite workpiece at or adjacent a cutting location of the purewaterjet to maintain a cutting environment at the cutting location whichis, apart from the pure waterjet, substantially devoid of fluid orparticulate matter.

The method of trimming the fiber reinforced polymer composite workpiecemay further include: maintaining a terminal end of the cutting head awayfrom the fiber reinforced polymer composite workpiece at a distance thatexceeds a threshold distance while directing the pure waterjet to passthrough and pierce the fiber reinforced polymer composite workpiece, andsubsequently, moving and maintaining the terminal end of the cuttinghead relatively closer to the fiber reinforced polymer compositeworkpiece while trimming the fiber reinforced polymer composite materialto the final component profile.

The method of trimming the fiber reinforced polymer composite workpiecemay further include introducing a gas stream into a path of the purewaterjet to alter a coherence of the pure waterjet during at least aportion of the trimming method.

Moving one of the cutting head and the fiber reinforced polymercomposite workpiece relative to the other along the predetermined pathmay include moving the cutting head with a multi-axis manipulator whilethe fiber reinforced polymer composite workpiece remains stationary. Inother instances, moving one of the cutting head and the fiber reinforcedpolymer composite workpiece relative to the other along thepredetermined path may include moving the fiber reinforced polymercomposite workpiece with a multi-axis manipulator while the cutting headremains stationary.

The method of trimming the fiber reinforced polymer composite workpiecemay further include maintaining a linear power density of the purewaterjet above a threshold linear power density sufficient to cut thefiber reinforced polymer composite workpiece along the final componentprofile without delamination, splintering, fraying or unacceptable fiberpullout or fiber fracture.

The method of trimming the fiber reinforced polymer composite workpiecemay further include controlling a cutting speed based on a plurality ofoperating parameters including material thickness, material type,operating pressure and orifice size. The plurality of operatingparameters may further include a tolerance level.

A method of trimming a fiber reinforced polymer composite workpiece mayalso be provided which comprises controlling a cutting speed based on aplurality of operating parameters to maintain backside linear defectsconsisting of small localized areas of delamination below a thresholdacceptable defect level.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a view of an example high-pressure waterjet cutting system,according to one embodiment, which comprises a multi-axis manipulator(e.g., gantry motion system) supporting a cutting head assembly at aworking end thereof for trimming fiber reinforced polymer compositeworkpieces.

FIG. 2 is a view of an example high-pressure waterjet cutting system,according to another embodiment, which comprises a multi-axismanipulator (e.g., multi-axis robotic arm) supporting a cutting headassembly at a working end thereof for trimming fiber reinforced polymercomposite workpieces.

FIG. 3 is a view of an example high-pressure waterjet cutting system,according to yet another embodiment, which comprises a multi-axismanipulator (e.g., multi-axis robotic arm) for manipulating fiberreinforced polymer composite workpieces beneath a cutting head assemblyfor trimming purposes.

FIG. 4 is a view of an example fiber reinforced polymer compositeworkpiece which may be trimmed via the methods and systems describedherein.

FIG. 5 is a skewed isometric view of a portion of a cutting headassembly, according to one embodiment, that may be used with the examplehigh-pressure waterjet cutting systems shown in FIGS. 1 through 3 forcutting fiber reinforced polymer composite workpieces, such as theexample workpiece of FIG. 4.

FIG. 6 is a cross-sectional side view of the portion of the cutting headassembly of FIG. 5.

FIG. 7 is a skewed isometric view of the portion of the cutting headassembly of FIG. 5 showing the cutting head assembly from anotherviewpoint.

FIG. 8 is a skewed isometric view of a nozzle component of the cuttinghead assembly shown in FIG. 5 from one viewpoint, showing some ofseveral internal passages thereof.

FIG. 9 is a skewed isometric view of the nozzle component of FIG. 8 fromthe same viewpoint, showing other internal passages thereof.

FIG. 10 is a skewed isometric view of the nozzle component of FIG. 8from a different viewpoint, showing other internal passages thereof.

FIGS. 11A-11C are microscopic images of an edge of a fiber reinforcedpolymer composite workpiece cut with a pure waterjet in accordance withtrimming methods disclosed herein.

FIG. 12 is a graph illustrating the effect of pressure and orifice sizeon acceptable cutting speed.

FIG. 13 is a graph illustrating variations in maximum cutting speed inrelation to operating pressure and orifice size.

FIG. 14 is a graph illustrating variations in acceptable cutting speedin relation to material thickness for each of two different operatingpressures.

FIG. 15 is a graph charting a percentage of backside linear defectsconsisting of small localized areas of delamination in relation tocutting speed under different operating parameters.

DETAILED DESCRIPTION

In the following description, certain specific details are set forth inorder to provide a thorough understanding of various disclosedembodiments. However, one of ordinary skill in the relevant art willrecognize that embodiments may be practiced without one or more of thesespecific details. In other instances, well-known structures associatedwith waterjet cutting systems and methods of operating the same may notbe shown or described in detail to avoid unnecessarily obscuringdescriptions of the embodiments. For instance, well known controlsystems and drive components may be integrated into the waterjet cuttingsystems to facilitate movement of the waterjet cutting head assemblyrelative to the workpiece or work surface to be processed. These systemsmay include drive components to manipulate the cutting head aboutmultiple rotational and translational axes, as is common in multi-axismanipulators of waterjet cutting systems. Example waterjet cuttingsystems may include a waterjet cutting head assembly coupled to agantry-type motion system, as shown in FIG. 1, a robotic arm motionsystem, as shown in FIG. 2, or other motion system for moving thecutting head relative to a workpiece. In other instances, a robotic armmotion system or other motion system may manipulate the workpiecerelative to a cutting head, as shown in FIG. 3.

Unless the context requires otherwise, throughout the specification andclaims which follow, the word “comprise” and variations thereof, such as“comprises” and “comprising,” are to be construed in an open, inclusivesense, that is as “including, but not limited to.”

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment. Thus, the appearances of the phrases “in one embodiment” or“in an embodiment” in various places throughout this specification arenot necessarily all referring to the same embodiment. Furthermore, theparticular features, structures, or characteristics may be combined inany suitable manner in one or more embodiments.

As used in this specification and the appended claims, the singularforms “a,” “an,” and “the” include plural referents unless the contentclearly dictates otherwise. It should also be noted that the term “or”is generally employed in its sense including “and/or” unless the contentclearly dictates otherwise.

Embodiments described herein provide methods of trimming fiberreinforced polymer composite workpieces with a pure waterjet dischargedfrom a cutting head in liquid phase unladened with solid particles at orabove a threshold operating pressure of at least 60,000 psi and incombination with other cutting parameters to provide a final componentprofile without delamination, splintering, fraying or unacceptable fiberpullout or fiber fracture.

As used herein, the term cutting head or cutting head assembly may refergenerally to an assembly of components at a working end of the waterjetmachine or system, and may include, for example, an orifice member, suchas a jewel orifice, through which fluid passes during operation togenerate a high-pressure waterjet, a nozzle component (e.g., nozzle nut)for discharging the high-pressure waterjet and surrounding structuresand devices coupled directly or indirectly thereto to move in unisontherewith. The cutting head may also be referred to as an end effectoror nozzle assembly.

The waterjet cutting system may operate in the vicinity of a supportstructure which is configured to support a workpiece to be processed bythe system. The support structure may be a rigid structure or areconfigurable structure suitable for supporting one or more workpieces(e.g., fiber reinforced polymer composite automotive parts) in aposition to be cut, trimmed or otherwise processed.

FIG. 1 shows an example embodiment of a waterjet cutting system 10. Thewaterjet cutting system 10 includes a catcher tank assembly 11 having awork support surface 13 (e.g., an arrangement of slats) that isconfigured to support a workpiece 14 to be processed by the system 10.The waterjet cutting system 10 further includes a bridge assembly 15which is movable along a pair of base rails 16 and straddles the catchertank assembly 11. In operation, the bridge assembly 15 can move back andforth along the base rails 16 with respect to a translational axis X toposition a cutting head assembly 12 of the system 10 for processing theworkpiece 14. A tool carriage 17 may be movably coupled to the bridgeassembly 15 to translate back and forth along another translational axisY, which is aligned perpendicularly to the aforementioned translationalaxis X. The tool carriage 17 may be configured to raise and lower thecutting head assembly 12 along yet another translational axis Z to movethe cutting head assembly 12 toward and away from the workpiece 14. Oneor more manipulable links or members may also be provided intermediatethe cutting head assembly 12 and the tool carriage 17 to provideadditional functionality.

As an example, the waterjet cutting system 10 may include a forearm 18rotatably coupled to the tool carriage 17 for rotating the cutting headassembly 12 about an axis of rotation, and a wrist 19 rotatably coupledto the forearm 18 to rotate the cutting head assembly 12 about anotheraxis of rotation that is non-parallel to the aforementioned rotationalaxis. In combination, the rotational axes of the forearm 18 and wrist 19can enable the cutting head assembly 12 to be manipulated in a widerange of orientations relative to the workpiece 14 to facilitate, forexample, cutting of complex profiles. The rotational axes may convergeat a focal point which, in some embodiments, may be offset from the endor tip of a nozzle component (e.g., nozzle component 120 of FIGS. 8through 10) of the cutting head assembly 12. The end or tip of thenozzle component of the cutting head assembly 12 is preferablypositioned at a desired standoff distance from the workpiece 14 or worksurface to be processed. The standoff distance may be selected ormaintained at a desired distance to optimize the cutting performance ofthe waterjet. For example, in some embodiments, the standoff distancemay be maintained at about 0.20 inch (5.1 mm) or less, or in someembodiments at about 0.10 inch (2.5 mm) or less. In other embodiments,the standoff distance may vary over the course of a trimming operationor during a cutting procedure, such as, for example, when piercing theworkpiece. In some instances, the nozzle component of the waterjetcutting head may be particularly slim or slender to enable, among otherthings, inclining of the nozzle component relative to the workpiece withminimal stand-off distance (e.g., a 30 degree inclination with standoffdistance less than or equal to about 0.5 inch (12.7 mm)).

During operation, movement of the cutting head assembly 12 with respectto each of the translational axes and one or more rotational axes may beaccomplished by various conventional drive components and an appropriatecontrol system 20 (FIG. 1). The control system may generally include,without limitation, one or more computing devices, such as processors,microprocessors, digital signal processors (DSP), application-specificintegrated circuits (ASIC), and the like. To store information, thecontrol system may also include one or more storage devices, such asvolatile memory, non-volatile memory, read-only memory (ROM), randomaccess memory (RAM), and the like. The storage devices can be coupled tothe computing devices by one or more buses. The control system mayfurther include one or more input devices (e.g., displays, keyboards,touchpads, controller modules, or any other peripheral devices for userinput) and output devices (e.g., display screens, light indicators, andthe like). The control system can store one or more programs forprocessing any number of different workpieces according to variouscutting head movement instructions. The control system may also controloperation of other components, such as, for example, a secondary fluidsource, a vacuum device and/or a pressurized gas source coupled to thepure waterjet cutting head assemblies and components described herein.The control system, according to one embodiment, may be provided in theform of a general purpose computer system. The computer system mayinclude components such as a CPU, various I/O components, storage, andmemory. The I/O components may include a display, a network connection,a computer-readable media drive, and other I/O devices (a keyboard, amouse, speakers, etc.). A control system manager program may beexecuting in memory, such as under control of the CPU, and may includefunctionality related to, among other things, routing high-pressurewater through the waterjet cutting systems described herein, providing aflow of secondary fluid to adjust or modify the coherence of adischarged fluid jet and/or providing a pressurized gas stream toprovide for unobstructed pure waterjet cutting of a fiber reinforcedpolymer composite workpiece.

Further example control methods and systems for waterjet cuttingsystems, which include, for example, CNC functionality, and which areapplicable to the waterjet cutting systems described herein, aredescribed in Flow's U.S. Pat. No. 6,766,216, which is incorporatedherein by reference in its entirety. In general, computer-aidedmanufacturing (CAM) processes may be used to efficiently drive orcontrol a waterjet cutting head along a designated path, such as byenabling two-dimensional or three-dimensional models of workpiecesgenerated using computer-aided design (i.e., CAD models) to be used togenerate code to drive the machines. For example, in some instances, aCAD model may be used to generate instructions to drive the appropriatecontrols and motors of a waterjet cutting system to manipulate thecutting head about various translational and/or rotational axes to cutor process a workpiece as reflected in the CAD model. Details of thecontrol system, conventional drive components and other well-knownsystems associated with waterjet cutting systems, however, are not shownor described in detail to avoid unnecessarily obscuring descriptions ofthe embodiments. Other known systems associated with waterjet cuttingsystems include, for example, a high-pressure fluid source (e.g., directdrive and intensifier pumps with pressure ratings ranging from about60,000 psi to 110,000 psi and higher) for supplying high-pressure fluidto the cutting head.

According to some embodiments, the waterjet cutting system 10 includes apump, such as, for example, a direct drive pump or intensifier pump (notshown), to selectively provide a source of high-pressure water at anoperating pressure of at least 60,000 psi or between about 60,000 psiand about 110,000 psi or higher. The cutting head assembly 12 of thewaterjet cutting system 10 is configured to receive the high-pressurewater supplied by the pump and to generate a high-pressure pure waterjetfor processing workpieces, including, in particular, fiber reinforcedpolymer composite workpieces. A fluid distribution system (not shown) influid communication with the pump and the cutting head assembly 12 isprovided to assist in routing high-pressure water from the pump to thecutting head assembly 12.

FIG. 2 shows another example embodiment of a waterjet cutting system10′. According to this example embodiment, the waterjet cutting system10′ includes a cutting head assembly 12′ that is supported at the end ofa multi-axis manipulator in the form of a multi-axis robotic arm 21. Inthis manner, the multi-axis robotic arm 21 can manipulate the cuttinghead assembly 12′ in space to process workpieces supported by a separateworkpiece support structure or fixture (not shown).

FIG. 3 shows yet another embodiment of a waterjet cutting system 10″.According to this example embodiment, the waterjet cutting system 10″includes a cutting head assembly 12″ that is supported opposite a jetreceiving receptacle 23 via a rigid support structure 26. As shown inFIG. 3, the jet receiving receptacle 23 may be coupled to the supportstructure 26 or other foundational structure in a manner that enables aclearance gap distance D between the cutting head assembly 12″ and aninlet aperture 24 of the jet receiving receptacle 23 to be adjusted. Forexample, in some embodiments, a linear positioner 30 may be providedintermediately between the support structure 26 and the jet receivingreceptacle 23 to enable the jet receiving receptacle 23 to becontrollably moved toward and away from the cutting head assembly 12″,as represented by the arrows labeled 32. Example linear positioners 30include HD Series linear positioners available from theElectromechanical Automation Division of Parker Hannifin Corporationlocated in Irwin, Pa. The linear positioner 30 may be coupled to thesupport structure 26 with clamps or other fastening devices and the jetreceiving receptacle 23 may be coupled to the linear positioner 30 by asupport arm or other structural member.

The linear positioner 30 may include a motor 36 in communication with acontrol system to enable controlled movement of the linear positioner 30and adjustment of the clearance gap distance D before, during and/orafter workpiece processing operations. In this manner, the inletaperture 24 of the jet receiving receptacle 23 can be maintained inclose proximity to a discharge side of a workpiece 14″ to be processed.The clearance gap distance D may be adjusted to accommodate workpieces14″ of different thicknesses or of varying thicknesses. In someembodiments, the clearance gap distance D may be adjusted duringprocessing of a workpiece 14″ (or a portion thereof) to reduce orminimize a gap between a rear discharge surface of the workpiece 14″ andthe inlet aperture 24 of the jet receiving receptacle 23 while amulti-axis manipulator in the form of a robotic arm 22 moves theworkpiece 14″ beneath the cutting head assembly 12″.

Although the example embodiment of FIG. 3 illustrates the jet receivingreceptacle 23 as moving relative to a stationary cutting head assembly12″, it is appreciated that a variation of the aforementioned fluid jetsystem 10″ may be provided in which the jet receiving receptacle 23 isfixed relative to the support structure 26 and wherein the linearpositioner 30 is provided between the support structure 26 and thecutting head assembly 12″ to enable the cutting head assembly 12″ to becontrollably moved toward and away from the jet receiving receptacle 23while the robotic arm 22 moves the workpiece 14″ beneath the cuttinghead assembly 12″. In still other instances, both of the cutting headassembly 12″ and the jet receiving receptacle 23 may remain staticthroughout a trimming operation.

The waterjet cutting systems 10, 10′, 10″ described herein, andvariations thereof, may be used in particular to trim fiber reinforcedpolymer composite workpieces, such as the example workpiece 50 shown inFIG. 4. The example workpiece 50 comprises a built-up thin shelledcarbon fiber reinforced polymer composite workpiece well suited forautomotive applications. The example workpiece 50 is shown in anunfinished state in which the fiber reinforced polymer compositematerial of the workpiece 50 extends beyond a final component profile 52thereof. An internal feature in the form of an aperture 54 having anouter profile 56 is shown within the confines of the final componentprofile 52 and may be cut using techniques similar to those describedherein for trimming the example workpiece 50 to the final componentprofile 52. The example workpiece 50 further includes one or moreindexing features 60 (e.g., notch, aperture or other indexing feature),shown within the markings labeled 58, for aligning and fixing theworkpiece 50 relative to the coordinate system of the waterjet cuttingsystem 10, 10′, 10″ for subsequent processing of the workpiece, such astrimming the workpiece 50 to the final component profile 52 and cuttingany internal features. In some instances, the workpiece 50 may includesuitable features for probing and assessing the position and orientationof the workpiece 50. In such instances, it may not be necessary toinclude indexing features 60 or to otherwise precisely control theposition and orientation of the workpiece 50 as the machining path maybe generated or otherwise adjusted based on data obtained by probing andassessing the position and orientation of the workpiece 50. The exampleworkpiece 50 shown in FIG. 4 further includes a plurality of raisedreinforcement ribs 66 to illustrate one example of numerous variationsin surface topography that may be present in the workpiece 50.

FIGS. 5 through 7 show one example of a portion of a cutting headassembly 112 that is particularly well suited for, among other things,cutting workpieces made of fiber reinforced polymer composite materials,such as carbon fiber reinforced polymer composites, with a pure waterjetin liquid form unladened with solid particles. The cutting head assembly112 may be used with the example high-pressure waterjet cutting systems10, 10′, 10″ shown in FIGS. 1 through 3, or may be coupled to othermotion systems, including other multi-axis manipulators, for processingworkpieces, such as the example carbon fiber reinforced polymercomposite workpiece shown in FIG. 4.

With reference to the cross-section shown in FIG. 6, the cutting headassembly 112 includes an orifice unit 114 through which a cutting fluid(i.e., water) passes during operation to generate a high-pressurewaterjet. The cutting head assembly 112 further includes a nozzle body116 having a fluid delivery passage 118 extending therethrough to routecutting fluid (i.e., high-pressure water) toward the orifice unit 114. Anozzle component 120 is coupled to the nozzle body 116 with the orificeunit 114 positioned or sandwiched therebetween. The nozzle component 120may be removably coupled to the nozzle body 116, for example, by athreaded connection 122 or other coupling arrangement. Coupling of thenozzle component 120 to the nozzle body 116 may urge the orifice unit114 into engagement with the nozzle body 116 to create a sealtherebetween, such as, for example, a metal-to-metal seal.

The nozzle component 120 can have a one-piece construction and can bemade, in whole or in part, of one or more metals (e.g., steel,high-strength metals, etc.), metal alloys, or the like. The nozzlecomponent 120 may include threads or other coupling features forcoupling to other components of cutting head assembly 112.

The orifice unit 114 may include an orifice mount 130 and an orificemember 132 (e.g., jewel orifice) supported thereby for generating ahigh-pressure fluid jet as high-pressure fluid (e.g., water) passesthrough an opening 134 (i.e., an orifice) in the orifice member 132. Afluid jet passage 136 may be provided in the orifice mount 130downstream of the orifice member 132 through which the jet passes duringoperation. The orifice mount 130 is fixed with respect to the nozzlecomponent 120 and includes a recess dimensioned to receive and hold theorifice member 132. The orifice member 132, in some embodiments, is ajewel orifice or other fluid jet or cutting stream producing device usedto achieve the desired flow characteristics of the resultant fluid jet.The opening of the orifice member 132 can have a diameter in a range ofabout 0.001 inch (0.025 mm) to about 0.020 inch (0.508 mm). In someembodiments, the orifice member 132 has a diameter in the range of about0.005 inch (0.127 mm) to about 0.010 inch (0.254 mm).

As shown in FIG. 6, the nozzle body 116 may be coupled to ahigh-pressure cutting fluid source 140, such as, for example, a sourceof high-pressure water (e.g., a direct drive or intensifier pump).During operation, high-pressure water from the cutting fluid source 140may be controllably fed into the fluid delivery passage 118 of thenozzle body 116 and routed toward the orifice unit 114 to generate thejet (not shown), which is ultimately discharged from the cutting headassembly 112 through an outlet 142 at the terminal end of a waterjetpassage 144 that extends through the nozzle component 120 along alongitudinal axis A thereof.

Further details of internal passages of the nozzle component 120,including the waterjet passage 144, are shown and described withreference to FIGS. 8 through 10.

With reference to FIG. 8, the waterjet passage 144 is shown extendingthrough a body 121 of the nozzle component 120 along longitudinal axisA. The waterjet passage 144 includes an inlet 146 at an upstream end 148thereof and the outlet 142 at a downstream end 149 thereof.

At least one jet alteration passage 150 may be provided within thenozzle component 120 for adjusting, modifying or otherwise altering thejet that is discharged from the outlet 142 of the nozzle component 120.The jet alteration passage 150 may extend through the body 121 of thenozzle component 120 and intersect with the waterjet passage 144 betweenthe inlet 146 and the outlet 142 thereof to enable such alteration ofthe waterjet during operation. More particularly, jet alteration passage150 may extend through the body 121 of the nozzle component 120 andinclude one or more downstream portions 152 that intersect with thewaterjet passage 144 so that a secondary fluid (e.g., water, air orother gas) passed through the jet alteration passage 150 duringoperation may be directed to impact the fluid jet travelingtherethrough. As an example, the jet alteration passage 150 may includea plurality of distinct downstream portions 152 that are arranged suchthat respective secondary fluid streams discharged therefrom impact thefluid jet traveling through the waterjet passage 144. The exampleembodiment shown in FIG. 8 includes three distinct downstream portions152 that are arranged in this manner; however, it is appreciated thattwo, four or more downstream passage portions 152 may be arranged insuch a manner.

Two or more of the downstream portions 152 of the passage 150 may joinat an upstream junction 154. The upstream junction 154 may be, forexample, a generally annular passage portion that is in fluidcommunication with an upstream end of each of the downstream passageportions 152, as shown in FIG. 8. The downstream portions 152 of the jetalteration passage 150 may be bridge passageways that extend between thegenerally annular passage portion and the waterjet passage 144. Thebridge passageways may be spaced circumferentially about the waterjetpassage 144 in a regular pattern. For example, the downstream portions152 shown in FIG. 8 include three distinct bridge passageways spacedabout the waterjet passage 144 in 120 degree intervals. In otherinstances, the bridge passageways may be spaced circumferentially aboutthe waterjet passage 144 in an irregular pattern. Moreover, each of thebridge passageways may include a downstream end that is configured todischarge a secondary fluid into the waterjet passage 144 at an anglethat is inclined toward the outlet 142 of the waterjet passage 144. Inthis manner, secondary fluid introduced through the jet alterationpassage 150 may impact the jet passing through the waterjet passage 144at an oblique trajectory.

The downstream portions 152 of the jet alteration passage 150 may besub-passageways that are configured to simultaneously discharge asecondary fluid from a secondary fluid source 158 (FIGS. 5 through 7)into a path of the waterjet passing through the waterjet passage 144during operation. Downstream outlets 153 of the sub-passageways mayintersect with the waterjet passage 144 such that the outlets 153collectively define at least a majority of a circumferential section ofthe waterjet passage 144 which has a height defined by a correspondingheight of the outlets 153 intersecting with the waterjet passage 144. Insome instances, the downstream outlets 153 of the sub-passageways mayintersect with the waterjet passage 144 such that the outlets 153collectively define at least seventy-five percent of the circumferentialsection of the waterjet passage 144. Moreover, in some instances, theoutlets 153 may overlap or nearly overlap with each other at theintersection with the waterjet passage 144.

The upstream junction 154 of the jet alteration passage 150 may be influid communication with a port 156 directly or via an intermediateportion 155. The port 156 may be provided for coupling the jetalteration passage 150 of the nozzle component 120 to the secondaryfluid source 158 (FIGS. 5 through 7). With reference to FIG. 5 or FIG.7, the port 156 may be threaded or otherwise configured to receive afitting, adapter or other connector 157 for coupling the jet alterationpassage 150 to the secondary fluid source 158 via a supply conduit 159.Intermediate valves (not shown) or other fluid control devices may beprovided to assist in controlling the delivery of a secondary fluid(e.g., water, air or other gas) to the jet alteration passage 150 andultimately into the waterjet passing through the waterjet passage 144.In other instances, the port 156 may be provided for coupling the jetalteration passage 150 to a vacuum source (not shown) for generating avacuum within the jet alteration passage 150 sufficient to alter flowcharacteristics of the waterjet passing through the waterjet passage144. The jet alteration passage 150 may be used intermittently orcontinuously during a portion of a cutting operation to adjust jetcoherence or other jet characteristics. For example, in some instances,a secondary fluid, such as, for example, water or air, may be introducedinto the waterjet via the jet alteration passage 150 during a piercingor drilling operation.

With reference to FIG. 9, an environment control passage 160 may beprovided within the nozzle component 120 for discharging a pressurizedgas stream to impinge on an exposed surface of a workpiece at oradjacent where the waterjet pierces or cuts through the workpiece duringa cutting operation (i.e., the waterjet impingement location). Theenvironment control passage 160 may extend through a body 121 of thenozzle component 120 and include one or more downstream portions 162that are aligned relative to the waterjet passage 144 (FIGS. 6, 8 and10) so that air or other gas passed through the environment controlpassage 160 during operation is directed to impinge on the workpiece ator adjacent the waterjet impingement location. As an example, theenvironment control passage 160 may include a plurality of distinctdownstream portions 162 that are arranged such that respective gasstreams discharged from outlets 163 thereof converge in a downstreamdirection at or near the waterjet impingement location.

With reference to FIG. 7, the gas streams discharged from the outlets163 of the downstream portions 162 may follow respective trajectories161 that intersect with a trajectory 123 of the discharged jet. Thetrajectories 161 of the gas streams may intersect with a trajectory 123of the discharged jet at an intersection location 124, for example,which is at or near the focal point or standoff distance of the waterjetcutting system 10, 10′, 10″. In some instances, the intersectionlocation 124 may be slightly short of the focal point or standoffdistance. In other instances, the intersection location 124 may beslightly beyond the focal point or standoff distance such that eachrespective gas stream trajectory 161 intersects with the exposed surfaceof the workpiece prior to reaching the waterjet impingement location andis then directed by the surface of the workpiece to change direction andflow across the waterjet impingement location.

Although the example environment control passage 160 shown in FIG. 9shows three distinct downstream portions 162 that converge in adownstream direction, it is appreciated that two, four or moredownstream passage portions 162 may be arranged in such a manner. Inother instances, a single downstream passage portion 162 may beprovided. In addition, in some embodiments, one or more gas streams maybe directed generally collinearly with the discharged jet to form ashroud around the jet.

With continued reference to FIG. 9, two or more of the downstreamportions 162 of the passage 160 may join at an upstream junction 164.The upstream junction 164 may be, for example, a generally annularpassage that is in fluid communication with an upstream end of each ofthe downstream passage portions 162, as shown in FIG. 9. The downstreampassage portions 162 of the environment control passage 160 may bedistinct sub-passageways that extend between the generally annularpassage portion and an external environment of the nozzle component 120.The downstream passage portions 162 of the environment control passage160 may be spaced circumferentially about the waterjet passage 144 in aregular pattern. For example, the downstream passage portions 162 shownin FIG. 9 include three distinct sub-passageways spaced about thewaterjet passage 144 in 120 degree intervals. In other instances, thedownstream passage portions 162 may be spaced circumferentially aboutthe waterjet passage 144 in an irregular pattern.

In some instances, the downstream passage portions 162 may be configuredto simultaneously discharge air or other gas from a common pressurizedgas source 168 (FIGS. 5 and 7) to impinge on the workpiece at oradjacent the waterjet impingement location. In this manner, pressurizedair or other gas introduced through the environment control passage 160may impinge or impact on an exposed surface of the workpiece and clearthe same of any obstructions (e.g., standing water droplets orparticulate matter) so that the waterjet may cut through the workpiecein a particularly precise manner. Again, in other embodiments, one ormore gas streams may be directed generally collinearly with thedischarged jet to form a shroud around the jet for maintaining anenvironment around the cutting location to be free of obstructions suchas standing water droplets or particulate matter.

The upstream junction 164 may be in fluid communication with a port 166directly or via an intermediate portion 165. The port 166 may beprovided for coupling the environment control passage 160 of the nozzlecomponent 120 to a pressurized gas source 168 (FIGS. 5 and 7). Withreference to FIG. 5 or FIG. 7, the port 166 may be threaded or otherwiseconfigured to receive a fitting, adapter or other connector 167 forcoupling the environmental control passage 160 to the pressurized gassource 168 via a supply conduit 169. Intermediate valves (not shown) orother fluid control devices may be provided to assist in controlling thedelivery of pressurized gas to the environment control passage 160 andultimately to the exposed surface of the workpiece that is to beprocessed.

With reference to FIG. 10, a condition detection passage 170 may beprovided within the nozzle component 120 to enable detection of acondition of the orifice member 132 (FIG. 6) that is used to generatethe waterjet. The condition detection passage 170 may extend through thebody 121 of the nozzle component 120 and include one or more downstreamportions 172 that intersect with the waterjet passage 144 at an upstreamend thereof so that a vacuum level may be sensed that is indicative of acondition of the orifice member 132. As an example, the conditiondetection passage 170 may include a curvilinear passageway 175 thatintersects with the waterjet passage 144 near and downstream of anoutlet of the fluid jet passage 136 of the orifice mount 130. Thecondition detection passage 170 may be in fluid communication with aport 176 that may be provided for coupling the condition detectionpassage 170 of the nozzle component 120 to a vacuum sensor 178, asshown, for example, in FIGS. 5 and 7. With reference to FIG. 5 or FIG.7, the port 176 may be threaded or otherwise configured to receive afitting, adapter or other connector 177 for coupling the conditiondetection passage 170 to the vacuum sensor 178 via a supply conduit 179.

With reference to FIG. 6, the nozzle component 120 may further include anozzle body cavity 180 for receiving a downstream end of the nozzle body116 and an orifice mount receiving cavity or recess 182 to receive theorifice mount 130 of the orifice unit 114 when assembled. The orificemount receiving cavity or recess 182 may be sized to assist in aligningthe orifice unit 114 along the axis A of the waterjet passage 144. Forinstance, orifice mount receiving cavity or recess 182 may comprise agenerally cylindrical recess that is sized to insertably receive theorifice mount 130 of the orifice unit 114. The orifice receiving cavityor recess 182 may be formed within a downstream end of the nozzle bodycavity 180.

With reference to FIG. 10, the nozzle component 120 may further includea vent passage 192 extending between the nozzle body cavity 180 and anexternal environment of the nozzle component 120 at vent outlet 190. Thevent passage 192 and vent outlet 190 may serve to relieve pressure thatmay otherwise build within an internal cavity formed around the orificeunit 114 between the nozzle body 116 and the nozzle component 120, asbest shown in FIG. 6.

According to the embodiment shown in FIGS. 5 through 10, the nozzlecomponent 120 has a unitary or one-piece body 121 that may be formedfrom an additive manufacturing or casting process using a material withmaterial property characteristics (e.g., strength) suitable forhigh-pressure waterjet applications. For instance, in some embodiments,the nozzle component 120 may be formed by a direct metal laser sinteringprocess using 15-5 stainless steel or other steel materials. In otherinstances, a nozzle component 120 may include a unitary or one-piecebody formed by other machining or manufacturing processes, such as, forexample, subtractive machining processes (e.g., drilling, milling,grinding, etc.). The nozzle component 120 may undergo heat treatment orother manufacturing processes to alter the physical properties of thenozzle component 120, such as, for example, increasing the hardness ofthe nozzle component 120. Although the example nozzle component 120 isshown as having a generally cylindrical body with an array of ports 156,166, 176 protruding from a side thereof, it is appreciated that in otherembodiments, the nozzle component 120 may take on different forms andmay have ports 156, 166, 176 located at different positions and withdifferent orientations.

In view of the above, it will be appreciated that a nozzle component 120for high-pressure waterjet cutting systems 10, 10′, 10″ may be providedin accordance with various aspects described herein, which isparticularly well adapted for receiving a high-pressure pure waterjetunladened with abrasive particles or other solid particles, andoptionally receiving a flow of secondary fluid and/or a flow ofpressurized gas to enable jet coherence adjustment and/or control of acutting environment while discharging the pure waterjet towards anexposed surface of a fiber reinforced polymer composite workpiece fortrimming the same. The nozzle component 120 may include complex passages(e.g., passages with curvilinear trajectories and/or varyingcross-sectional shapes and/or sizes) that are well suited for routingfluid or other matter in particularly efficient and reliable formfactors. Benefits of embodiments of such a nozzle component 120 includethe ability to provide enhanced flow characteristics and/or to reduceturbulence within the internal passages. This can be particularlyadvantageous when space constraints might not otherwise providesufficient space for developing favorable flow characteristics. Forexample, a low profile nozzle component 120 may be desired when cuttingworkpieces within confined spaces. Including a nozzle component 120 withinternal passages as described herein can enable such a low profilenozzle component 120 to generate a fluid jet with desired jetcharacteristics despite such space constraints. In addition, the fatiguelife of such a nozzle component 120 may be extended by eliminating sharpcorners, abrupt transitions and other stress concentrating features.These and other benefits may be provided by the various aspects of thenozzle component 120 described herein.

In accordance with the various waterjet cutting systems 10, 10′, 10,″cutting head assemblies 12, 12′, 12″ and nozzle components 120 describedherein, methods that are particularly well adapted for trimming a fiberreinforced polymer composite workpiece are provided. One example methodincludes: providing a fiber reinforced polymer composite workpiece in anunfinished state in which fiber reinforced polymer composite material ofthe workpiece extends beyond a final component profile thereof;generating a pure waterjet via a cutting head in liquid phase unladenedwith solid particles at an operating pressure of at least 60,000 psi;directing the pure waterjet to pass through the fiber reinforced polymercomposite workpiece; and moving one of the cutting head and the fiberreinforced polymer composite workpiece relative to the other along apredetermined path while maintaining the operating pressure of at least60,000 psi such that the pure waterjet trims the fiber reinforcedpolymer composite material to the final component profile withoutdelamination, splintering, fraying or unacceptable fiber pullout orfiber fracture. Trimming the workpiece to a final component profilewithout delamination, splintering, fraying or unacceptable fiber pulloutor fiber fracture may be evidenced by an edge and adjacent surfaceswhich are free from delamination, splintering and fraying and which,under microscopic evaluation, show fibers with clean cuts without fiberdamage or pullout, as shown for example in representative FIGS. 11A-11C.According to some embodiments, the edge of the trimmed workpiece mayhave a surface roughness having an R_(a) value of about 22±5 microns oran R_(z) value of about 128±20 microns.

According to some embodiments, moving the cutting head and the fiberreinforced polymer composite workpiece relative to each other along thepredetermined path may include moving at a cutting speed based at leastin part on a thickness of the fiber reinforced polymer compositeworkpiece and a magnitude of the operating pressure.

Generally, holding other variables, such as thickness (t) of theworkpiece and standoff distance (Sod), constant, cutting speed may beincreased with increases in operating pressures (p) above 60,000 psi. Toillustrate this relationship, example cuts were performed on a carbonfiber reinforced polymer workpiece with a pure waterjet unladened withsolid particles under similar conditions at operating pressures of about70,000 psi (483 MPa) and about 87,000 psi (600 MPa) for each of twodifferent orifice sizes (dn), namely 0.005 inch (0.127 mm) and 0.007(0.178 mm), to assess acceptable cutting speeds. The results are shownon the graph of FIG. 12. Under the tested conditions, significantlyhigher acceptable cutting speeds were enabled when increasing theoperating pressure from about 70,000 psi (483 MPa) to about 87,000 psi(600 MPa). In addition, higher acceptable cutting speeds were enabledwhen increasing the orifice size from 0.005 inch (0.127 mm) to 0.007inch (0.178 mm), but to a less significant degree when compared to theeffects of changing the operating pressure. Acceptable cutting speedswere determined by identifying cutting speeds which produced workpieceedge quality lacking appreciable delamination, splintering, fraying orunacceptable fiber pullout or fiber fracture.

To further illustrate the relationship between acceptable or maximumcutting speed and orifice size (dn), example cuts were performed on acarbon fiber reinforced polymer workpiece having a material thickness(t) of about 0.125 inch (3.2 mm) with a pure waterjet unladened withsolid particles under similar conditions at operating pressures of about60,000 psi (414 MPa); about 70,000 psi (483 MPa); and about 87,000 psi(600 MPa) for each of three different orifice sizes (dn), namely 0.005inch (0.127 mm); 0.007 inch (0.178 mm); and 0.010 inch (0.254 mm). Theresults are shown on the graph of FIG. 13. Under the tested conditions,higher cutting speeds were enabled with increasing orifice size fororifices in a range of about 0.005 inch to about 0.010 inch. Thus, forat least a portion of the trimming method, the cutting speed may beselected based at least in part an orifice size of an orifice memberused to generate the pure waterjet, the cutting speed increasing withincreases in the orifice size for orifice sizes in a range of about0.005 inch to about 0.010 inch.

Generally, holding other variables, such as orifice size (dn) andstandoff distance (Sod), constant, acceptable cutting speed may beincreased with increases in operating pressures (p) above 60,000 psi andmay be increased with reductions in material thickness (t). Toillustrate these relationships, example cuts were performed on carbonfiber reinforced polymer workpieces with a pure waterjet unladened withsolid particles under similar conditions at operating pressures of about70,000 psi (483 MPa) and about 87,000 psi (600 MPa) for various materialthicknesses (t) to assess acceptable cutting speeds. The results areshown on the graph of FIG. 14. Under the tested conditions,significantly higher acceptable cutting speeds were again enabled whenincreasing the operating pressure from about 70,000 psi (483 MPa) toabout 87,000 psi (600 MPa). In addition, higher acceptable cuttingspeeds were enabled when reducing the material thickness. Again,acceptable cutting speeds were determined by identifying cutting speedswhich produced workpiece edge quality lacking appreciable delamination,splintering, fraying or unacceptable fiber pullout or fiber fracture.

To further illustrate the relationship between acceptable or maximumcutting speed and operating pressure (p), example cuts were performed oncarbon fiber reinforced polymer workpieces having a material thickness(t) of about 0.120 inch (3.05 mm) with a pure waterjet unladened withsolid particles under similar conditions at operating pressures of about70,000 psi (483 MPa) and about 87,000 psi (600 MPa) and percentages ofbackside linear defects consisting of small localized areas ofdelamination were recorded for each of two series of tests at fivedifferent linear cutting speeds. The results are shown on the graph ofFIG. 15. Under the tested conditions, cutting the carbon fiberreinforced polymer workpiece with an operating pressure (p) of about87,000 psi (600 MPa) resulted in a significantly smaller percentage oflinear defects than with an operating pressure (p) of about 70,000 psi(483 MPa) while enabling much higher acceptable cutting speeds. Thus, insome embodiments, a trimming method may be advantageously performedwhile maintaining operating pressure at or above 87,000 psi (600 MPa) tominimize or eliminate backside linear defects.

In view of the above, for at least a portion of the trimming method, thecutting speed may be selected relative to, among other factors, materialthickness and operating pressure to satisfy at least one of thefollowing sets of conditions when cutting medium strength carbon fiberreinforced polymer composite workpieces or workpieces made of fiberreinforced polymer composites with similar material characteristics: thecutting speed is between about 3,000 mm/min and about 6,000 mm/min whenthe operating pressure is between about 60,000 psi and about 75,000 psiand the material thickness is about 1.00 mm±0.50 mm; the cutting speedis between about 500 mm/min and about 1,000 mm/min, when the operatingpressure is between about 60,000 psi and about 75,000 psi and thematerial thickness is about 2.50 mm±1.00 mm; the cutting speed isbetween about 100 mm/min and about 250 mm/min when the operatingpressure is between about 60,000 psi and about 75,000 psi and thematerial thickness is about 5.5 mm±2.00 mm; and the cutting speed isbetween about 20 mm/min and about 40 mm/min when the operating pressureis between about 60,000 psi and about 75,000 psi and the materialthickness is about 10.0 mm±2.50 mm. In other instances, for at least aportion of the trimming method, the cutting speed may be selectedrelative to, among other factors, the material thickness and theoperating pressure to satisfy at least one of the following sets ofconditions when cutting medium strength carbon fiber reinforced polymercomposite workpieces or workpieces made of fiber reinforced polymercomposites with similar material characteristics: the cutting speed isbetween about 8,000 mm/min and about 12,000 mm/min when the operatingpressure is between about 75,000 psi and about 90,000 psi and thematerial thickness is about 1.00 mm±0.50 mm; the cutting speed isbetween about 1,200 mm/min and about 2,000 mm/min when the operatingpressure is between about 75,000 psi and about 90,000 psi and thematerial thickness is about 2.50 mm±1.00 mm; the cutting speed isbetween about 300 mm/min and about 500 mm/min when the operatingpressure is between about 75,000 psi and about 90,000 psi and thematerial thickness is about 5.5 mm±2.00 mm; and the cutting speed isbetween about 75 mm/min and about 120 mm/min when the operating pressureis between about 75,000 psi and about 90,000 psi and the materialthickness is about 10.0 mm±2.50 mm.

Acceptable or maximum cutting speed may also be based at least in parton a type of fiber, a type of matrix material, and/or a type offabrication scheme of the fiber reinforced polymer composite workpiece.For example, the fiber reinforced polymer composite workpiece mayinclude carbon fibers, glass fibers, boron fibers, polyamide fibers orother types of fibers, may include different types of polymer matrixmaterials, and may be built up from layers of fibers, tape or clothimpregnated with the matrix materials, thereby resulting in reinforcedpolymer composite workpieces having different material characteristics,such as strength or hardness. Cutting speed may be selected based atleast in part on such material characteristics. For example, relativelyslower cutting speeds may be selected for harder composite materials,such as, for example, higher strength carbon fiber polymer compositescompared to lower strength polyamide fiber polymer composites.

According to some embodiments, the trimming method may includemaintaining a linear power density (jet power divided by jet diameter)of the pure waterjet above a threshold linear power density sufficientto cut the fiber reinforced polymer composite workpiece along the finalcomponent profile without delamination, splintering, fraying orunacceptable fiber pullout or fiber fracture. The threshold linear powerdensity may be dependent upon a variety of factors including materialtype and material thickness, and the actual linear power density of thepure waterjet may be determined mainly by the operating pressure andorifice size.

According to some embodiments, the trimming method may includecontrolling a cutting speed based on a plurality of operating parametersincluding material thickness, material type, operating pressure, andorifice size. For example, the cutting speed may be set relativelyhigher for thinner workpieces, for softer composites, under higheroperating pressures or when using larger orifice sizes. Other parametersmay include standoff distance and tolerance level. For example, someworkpieces may require tighter tolerance control and the cutting speedmay be adjusted accordingly (i.e., lower cutting speeds for strictertolerances and higher cutting speeds for looser tolerances). Tightertolerance control may be reflected in the amount of surface roughnessdesired or tolerated for a given application of the trimming methodsdescribed herein. Still other parameters may include a complexity of thecutting path, such as the degree of arcs or corners the jet isnegotiating while cutting. For example, relatively slower cutting speedsmay be used when approaching and navigating tighter corners and smallerradius arcs to assist in preventing delamination, while relativelyfaster cutting speeds may be used on straighter or straight cuts.

According to some embodiments, rather than preventing all delamination,a trimming method may comprise controlling the linear cutting speed tomaintain backside linear defects consisting of small localized areas ofdelamination below a threshold acceptable defect level, such as, forexample, less than 10% backside linear defects or less than 5% backsidelinear defects.

According to some embodiments, the trimming method may further comprisepiercing the fiber reinforced polymer composite workpiece at an areawithin the final component profile (e.g., at the location of aperture 54of FIG. 4) at any operating pressure (including below 60,000 psi) andcreating an aperture surrounded by a localized area of delamination ofan acceptable size, and thereafter moving one of the cutting head andthe fiber reinforced polymer composite workpiece relative to the otheralong another predetermined path while maintaining an operating pressureof at least 60,000 psi such that the pure waterjet cuts an internalfeature within the fiber reinforced polymer composite material andremoves the localized area of delamination. For example, with referenceto the aperture 54 of the example carbon fiber reinforced polymercomposite workpiece 50 of FIG. 4, the piercing operation may occur in acenter of the aperture 54, causing a localized area of delamination, andthen a spiral or other curvilinear path may be followed to approach theouter profile 56 nearly tangent thereto and then the cut may continuealong a path coincident with the outer profile 56 to form the aperture54 and to remove the localized area of delamination. In this manner,internal features with acceptable edge quality may be produced whileutilizing faster piercing techniques that might otherwise compromise theintegrity of the workpiece if the surrounding area was not subsequentlyremoved.

According to some embodiments, the trimming method may further comprisemaintaining a terminal end of the cutting head away from the fiberreinforced polymer composite workpiece at a distance that exceeds athreshold distance while directing the pure waterjet to pass through andpierce the fiber reinforced polymer composite workpiece, andsubsequently, moving and maintaining the terminal end of the cuttinghead relatively closer to the fiber reinforced polymer compositeworkpiece while trimming the fiber reinforced polymer composite materialto the final component profile. In this manner, the fiber reinforcedmaterials may be pierced with the nozzle component of the cutting headat a first standoff distance and subsequent cutting may commence withthe nozzle component at a second standoff distance that is less than thefirst standoff distance. Proceeding in this manner may minimize oreliminate delamination or fraying that might otherwise occur whenpiercing the workpiece with a pure waterjet.

According to some embodiments, the trimming method may further comprise,while moving the cutting head and the fiber reinforced polymer compositeworkpiece relative to each other along at least a portion of thepredetermined path, simultaneously directing a gas stream onto anexposed surface of the fiber reinforced polymer composite workpiece ator adjacent (e.g., ahead of) a cutting location of the pure waterjet tomaintain a cutting environment at the cutting location which is, apartfrom the pure waterjet, substantially devoid of fluid or particulatematter. In this manner, the path of the cut may be cleared of anystanding water or particulate matter that might otherwise comprise thequality of the cut. In some instances, an air shroud may be formedaround the pure waterjet in addition to or in lieu of the aforementionedgas stream.

According to some embodiments, the trimming method may further compriseintroducing a gas stream into a path of the pure waterjet to alter acoherence of the pure waterjet during at least a portion of the trimmingmethod. In this manner, coherence or other properties or characteristicsof the discharged jet can be selectively altered. In some instances, forexample, the jet may be altered during drilling, piercing or otherprocedures wherein it may be beneficial to reduce the energy of thewaterjet prior to impingement on the workpiece. This can reducedelamination and other defects when cutting fiber reinforced polymercomposite materials such as carbon fiber reinforced polymer composites.

According to some embodiments, moving one of the cutting head and thefiber reinforced polymer composite workpiece relative to the other alongthe predetermined path may include moving the cutting head with amulti-axis manipulator while the fiber reinforced polymer compositeworkpiece remains stationary. Alternatively, the fiber reinforcedpolymer composite workpiece may be moved with a multi-axis manipulatorwhile the cutting head remains stationary.

According to embodiments of the pure waterjet trimming methods describedherein, fixturing may be simplified when utilizing a pure waterjetbecause the pure waterjet is less destructive to support structuresunderlying the workpieces. Accordingly, some embodiments may includesupporting the workpiece with a support structure and allowing the purewaterjet to strike or impinge upon the support structure during at leasta portion of the trimming procedure. Moreover, utilizing the methodsdescribed herein and maintaining the linear power density of thedischarged pure waterjet above a threshold level required to cut thefiber reinforced polymer composite workpieces may eliminate a need tosupport the backside of the workpiece to be processed in areasimmediately adjacent the cutting locations, thereby further simplifyingfixturing.

Additional features and other aspects that may augment or supplement themethods described herein will be appreciated from a detailed review ofthe present disclosure. Moreover, aspects and features of the variousembodiments described above can be combined to provide furtherembodiments. These and other changes can be made to the embodiments inlight of the above-detailed description. In general, in the followingclaims, the terms used should not be construed to limit the claims tothe specific embodiments disclosed in the specification and the claims,but should be construed to include all possible embodiments along withthe full scope of equivalents to which such claims are entitled.

The invention claimed is:
 1. A method of trimming a fiber reinforcedpolymer composite workpiece, the method comprising: providing the fiberreinforced polymer composite workpiece in a post-molded or post cured,untrimmed state in which fiber reinforced polymer composite material ofthe fiber reinforced polymer composite workpiece extends beyond a finalcomponent profile thereof; and thereafter generating a pure waterjet viaa cutting head in liquid phase unladened with solid particles at anoperating pressure of at least 60,000 psi; directing the pure waterjetto pass through the fiber reinforced polymer composite material of thefiber reinforced polymer composite workpiece in the post-molded or postcured, untrimmed state; and moving at least one of the cutting head andthe fiber reinforced polymer composite workpiece relative to the otherat a cutting speed along a predetermined path while maintaining theoperating pressure of at least 60,000 psi such that the pure waterjettrims the fiber reinforced polymer composite material of the fiberreinforced polymer composite workpiece to the final component profilewherein the cutting speed is selected to produce an edge of the fiberreinforced polymer composite workpiece with a predetermined surfaceroughness having at least one of an R_(a) value of about 22 ±5 micronsand an R_(z) value of 128 ±20 microns.
 2. The method of claim 1 whereinmoving the cutting head and the fiber reinforced polymer compositeworkpiece relative to each other along the predetermined path includesmoving at a cutting speed based at least in part on a thickness of thefiber reinforced polymer composite workpiece and a magnitude of theoperating pressure.
 3. The method of claim 2 wherein the workpiece isreinforced with carbon fibers and wherein, for at least a portion of thetrimming method, the cutting speed is selected relative to the thicknessof the carbon fiber reinforced polymer composite workpiece and theoperating pressure to satisfy at least one of the following: the cuttingspeed is between about 3,000 mm/min and about 6,000 mm/min when theoperating pressure is between about 60,000 psi and about 75,000 psi andthe material thickness is about 1.00 mm±0.50 mm; the cutting speed isbetween about 500 mm/min and about 1,000 mm/min when the operatingpressure is between about 60,000 psi and about 75,000 psi and thematerial thickness is about 2.50 mm±1.00 mm; the cutting speed isbetween about 100 mm/min and about 250 mm/min when the operatingpressure is between about 60,000 psi and about 75,000 psi and thematerial thickness is about 5.5 mm±2.00 mm; and the cutting speed isbetween about 20 mm/min and about 40 mm/min when the operating pressureis between about 60,000 psi and about 75,000 psi and the materialthickness is about 10.0 mm±2.50 mm.
 4. The method of claim 2 wherein theworkpiece is reinforced with carbon fibers and wherein, for at least aportion of the trimming method, the cutting speed is selected relativeto the thickness of the carbon fiber reinforced polymer compositeworkpiece and the operating pressure to satisfy at least one of thefollowing: the cutting speed is between about 8,000 mm/min and about12,000 mm/min when the operating pressure is between about 75,000 psiand about 90,000 psi and the material thickness is about 1.00 mm±0.50mm; the cutting speed is between about 1,200 mm/min and about 2,000mm/min when the operating pressure is between about 75,000 psi and about90,000 psi and the material thickness is about 2.50 mm±1.00 mm; thecutting speed is between about 300 mm/min and about 500 mm/min when theoperating pressure is between about 75,000 psi and about 90,000 psi andthe material thickness is about 5.5 mm±2.00 mm; and the cutting speed isbetween about 75 mm/min and about 120 mm/min when the operating pressureis between about 75,000 psi and about 90,000 psi and the materialthickness is about 10.0 mm±2.50 mm.
 5. The method of claim 2 wherein thecutting speed is also based at least in part on a type of fiber, a typeof matrix material, and/or a type of fabrication scheme of the fiberreinforced polymer composite workpiece.
 6. The method of claim 5 whereinthe fiber reinforced polymer composite workpiece includes carbon fibers,glass fibers, boron fibers or polyamide fibers, and wherein the fiberreinforced polymer composite workpiece is built up from layers offibers, tape or cloth impregnated with the matrix material.
 7. Themethod of claim 2 wherein the cutting speed is also based at least inpart on an orifice size of an orifice member used to generate the purewaterjet, the cutting speed increasing with increases in the orificesize for orifice sizes in a range of about 0.005 inch to about 0.010inch.
 8. The method of claim 1 wherein generating the pure waterjet viathe cutting head in liquid phase unladened with solid particles includesgenerating the pure waterjet via an orifice member having a diameterless than about 0.010 inch.
 9. The method of claim 1 wherein generatingthe pure waterjet via the cutting head in liquid phase unladened withsolid particles includes generating the pure waterjet via an orificemember having a diameter of about 0.005 inch.
 10. The method of claim 1,further comprising: piercing the fiber reinforced polymer compositeworkpiece in the post-molded or post cured, untrimmed state at an areawithin the final component profile at any operating pressure andcreating an aperture surrounded by a localized area of delamination; andmoving one of the cutting head and the fiber reinforced polymercomposite workpiece relative to the other along another predeterminedpath while maintaining operating pressure of at least 60,000 psi suchthat the pure waterjet cuts an internal feature within the fiberreinforced polymer composite material and removes the localized area ofdelamination.
 11. The method of claim 1, further comprising: whilemoving the cutting head and the fiber reinforced polymer compositeworkpiece relative to each other along at least a portion of thepredetermined path, simultaneously directing a gas stream onto anexposed surface of the fiber reinforced polymer composite workpiece ator adjacent a cutting location of the pure waterjet to maintain acutting environment at the cutting location which is, apart from thepure waterjet, substantially devoid of fluid or particulate matter. 12.The method of claim 1, further comprising: maintaining a terminal end ofthe cutting head away from the fiber reinforced polymer compositeworkpiece at a first distance that exceeds a second distance whiledirecting the pure waterjet to pass through and pierce the fiberreinforced polymer composite workpiece, and subsequently, moving andmaintaining the terminal end of the cutting head at a third distancethat is less than or equal to the second distance while trimming thefiber reinforced polymer composite material to the final componentprofile.
 13. The method of claim 1, further comprising: introducing agas stream into a path of the pure waterjet to alter a coherence of thepure waterjet during at least a portion of the trimming method, such aswhen piercing or trimming the fiber reinforced polymer compositeworkpiece.
 14. The method of claim 1 wherein moving one of the cuttinghead and the fiber reinforced polymer composite workpiece relative tothe other along the predetermined path includes moving the cutting headwith a multi-axis manipulator while the fiber reinforced polymercomposite workpiece remains stationary.
 15. The method of claim 1wherein moving one of the cutting head and the fiber reinforced polymercomposite workpiece relative to the other along the predetermined pathincludes moving the fiber reinforced polymer composite workpiece with amulti-axis manipulator while the cutting head remains stationary. 16.The method of claim 1, further comprising: controlling a cutting speedbased on a plurality of operating parameters including materialthickness, material type, operating pressure and orifice size.
 17. Themethod of claim 16 wherein the plurality of operating parameters furtherinclude a tolerance level.
 18. The method of claim 1 wherein theworkpiece is reinforced with carbon fibers and wherein the carbon fiberreinforced polymer composite workpiece is an automotive component. 19.The method of claim 1 wherein moving at least one of the cutting headand the fiber reinforced polymer composite workpiece relative to theother includes producing an edge of the fiber reinforced polymercomposite workpiece with less than 10% backside linear defects.
 20. Themethod of claim 1, further comprising: engaging one or more indexingfeatures defined by the fiber reinforced polymer composite workpiece,thereby aligning the fiber reinforced polymer composite workpiecerelative to the cutting head.
 21. The method of claim 20, wherein theone or more indexing features are located outside the final componentprofile.
 22. The method of claim 10 wherein the predetermined path iscurvilinear and approaches the outer profile of the apertureapproximately tangent thereto.
 23. The method of claim 1, furthercomprising: generating an air shroud around the pure waterjet.
 24. Amethod of trimming a fiber reinforced polymer composite workpiece, themethod comprising: providing the fiber reinforced polymer compositeworkpiece in a post-molded or post cured, untrimmed state in which fiberreinforced polymer composite material of the fiber reinforced polymercomposite workpiece extends beyond a final component profile thereof,the fiber reinforced polymer composite workpiece having a thin shellstructure; and thereafter generating a pure waterjet via a cutting headin liquid phase unladened with solid particles at an operating pressureof at least 60,000 psi, the cutting head supported by a multi-axismanipulator; and moving the cutting head via the multi-axis manipulatorrelative to the fiber reinforced polymer composite workpiece along apredetermined path while directing the pure waterjet to pass through thefiber reinforced polymer composite material of the fiber reinforcedpolymer composite workpiece, maintaining the operating pressure of atleast 60,000 psi, and controlling a cutting speed based on a pluralityof operating parameters including material thickness, material type,operating pressure, standoff distance and orifice size, such that thepure waterjet trims the fiber reinforced polymer composite material ofthe fiber reinforced polymer composite workpiece to the final componentprofile thereby defining an edge of the fiber reinforced polymercomposite workpiece with a surface roughness having at least one of anR_(a)value of about 22 ±5 microns and an R_(z) value of 128 ±20 microns.